[clang][patch] Solve PR49479, File scope fp pragma should propagate to...

[clang][patch] Solve PR49479, File scope fp pragma should propagate to functions nested in struct, and initialization expressions

Previously, the CurFPFeatures state was set to command line settings before
semantic analysis of the nested member functions and initialization
expressions, that's not correct, it should use the pragma state which
is in effect at the lexical position.

Reviewed By: Erich Keane, Aaron Ballman

Differential Revision: https://reviews.llvm.org/D98211