[llvm] [Dexter] Replace clang with clang++ in various cross project tests (PR #65987)

[Shubham Sandeep Rastogi via llvm-commits]

rastogishubham wrote:

I tried to add `-isysroot` to the clang invocation by modifying lit.local.cfg, that takes care of error I saw in the clang invocation, but the tests don't pass.

```
FAIL: cross-project-tests :: debuginfo-tests/dexter-tests/ctor.cpp (2 of 2)
******************** TEST 'cross-project-tests :: debuginfo-tests/dexter-tests/ctor.cpp' FAILED ********************
Script:
--
: 'RUN: at line 4';   /Users/shubham/Development/llvm-project/build_ninja/bin/clang -isysroot /Users/shubham/apple-internal/Xcode-Rainbow/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX14.0.sdk  -std=gnu++11 -O0 -glldb /Users/shubham/Development/llvm-project/cross-project-tests/debuginfo-tests/dexter-tests/ctor.cpp -o /Users/shubham/Development/llvm-project/build_ninja/projects/cross-project-tests/debuginfo-tests/dexter-tests/Output/ctor.cpp.tmp
: 'RUN: at line 5';   "/opt/homebrew/opt/python at 3.11/bin/python3.11" "/Users/shubham/Development/llvm-project/cross-project-tests/debuginfo-tests/dexter/dexter.py" test --lldb-executable "/Users/shubham/Development/llvm-project/build_ninja/bin/lldb" --fail-lt 1.0 -w      --binary /Users/shubham/Development/llvm-project/build_ninja/projects/cross-project-tests/debuginfo-tests/dexter-tests/Output/ctor.cpp.tmp --debugger 'lldb' -- /Users/shubham/Development/llvm-project/cross-project-tests/debuginfo-tests/dexter-tests/ctor.cpp
--
Exit Code: 2

Command Output (stdout):
--
ctor.cpp: (0.0000)


--
```

Weirdly enough, when I run the same command line locally, it seems to work without an issue:

```
shubham at Mac-3004D6-2 cross-project-tests % /Users/shubham/Development/llvm-project/build_ninja/bin/clang -isysroot /Users/shubham/apple-internal/Xcode-Rainbow/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX14.0.sdk  -std=gnu++11 -O0 -glldb /Users/shubham/Development/llvm-project/cross-project-tests/debuginfo-tests/dexter-tests/ctor.cpp -o /Users/shubham/Development/llvm-project/build_ninja/projects/cross-project-tests/debuginfo-tests/dexter-tests/Output/ctor.cpp.tmp
shubham at Mac-3004D6-2 cross-project-tests % "/opt/homebrew/opt/python at 3.11/bin/python3.11" "/Users/shubham/Development/llvm-project/cross-project-tests/debuginfo-tests/dexter/dexter.py" test --lldb-executable "/Users/shubham/Development/llvm-project/build_ninja/bin/lldb" --fail-lt 1.0 -w      --binary /Users/shubham/Development/llvm-project/build_ninja/projects/cross-project-tests/debuginfo-tests/dexter-tests/Output/ctor.cpp.tmp --debugger 'lldb' -- /Users/shubham/Development/llvm-project/cross-project-tests/debuginfo-tests/dexter-tests/ctor.cpp
ctor.cpp: (1.0000)

shubham at Mac-3004D6-2 cross-project-tests % echo $?
0
```

So I am not sure of what is going on

https://github.com/llvm/llvm-project/pull/65987