RS6000 Allow builtin initialization regardless of mask

RS6000 Allow builtin initialization regardless of mask

  Disable the code that limits initialization of builtins based
on the rs6000_builtin_mask.  This allows all built-ins to be
properly referenced when building code using #pragma for cpu
targets newer than what was specified by the -mcpu default.
The use of built-ins is still properly limited by logic within
altivec_resolve_overloaded_builtin().

2020-03-30  Will Schmidt  <will_schmidt@vnet.ibm.com>

gcc/
    * config/rs6000/rs6000-call.c altivec_init_builtins(): Remove code
    to skip defining builtins based on builtin_mask.

gcc/testsuite/
    * gcc.target/powerpc/pragma_power6.c: New.
    * gcc.target/powerpc/pragma_power7.c: New.
    * gcc.target/powerpc/pragma_power8.c: New.
    * gcc.target/powerpc/pragma_power9.c: New.
    * gcc.target/powerpc/pragma_misc9.c: New.
    * gcc.target/powerpc/vsu/vec-all-nez-7.c: Update error message.
    * gcc.target/powerpc/vsu/vec-any-eqz-7.c: Update error message.