Set debug location to Coroutine call expression

[rastogishubham]

If debug info generation is enabled, set debug location to the coroutine call instruction to make sure there are no issues with invalid debug information in LTO.

This happens because in LTO, if a call to a function doesn't contain a debug location, we see the warning:

inlinable function call in a function with debug info must have a !dbg location

ld: warning: Invalid debug info found, debug info will be stripped

Which then strips the debug info from the entire .o file linked into the dylib.

[rastogishubham]

@swift-ci please test

[rastogishubham]

@swift-ci please test

[adrian-prantl]

@swift-ci smoke test

[adrian-prantl]

Error looks unrelated.

[rastogishubham]

Hmmm... Test failing with:

 ******************** TEST 'Swift(linux-x86_64) :: Misc/verify-swift-feature-testing.test-sh' FAILED ********************
20:23:07  Exit Code: 1
20:23:07  
20:23:07  Command Output (stdout):
20:23:07  --
20:23:07  /home/build-user/swift/test/IRGen/CoroutineAccessorsDebugLoc.swift: error: file enables 'CoroutineAccessors' but is missing '// REQUIRES: swift_feature_CoroutineAccessors'
20:23:07  
20:23:07  --
20:23:07  Command Output (stderr):

I will add the requires line and try again

[rastogishubham]

@swift-ci please test

[rastogishubham]

@swift-ci please smoke test