[gdb/testsuite] Fix capitalized test names

At https://sourceware.org/gdb/wiki/GDBTestcaseCookbook\
  #Follow_the_test_name_convention we find:
..
Test names should start with a lower case and don't need to end with a period
(they are not sentences).
...

Fix some capitalized test names.

Tested on x86_64-linux.

2018-10-18  Tom de Vries  <tdevries@suse.de>

	* gdb.ada/bp_inlined_func.exp: Fix capitalized test name.
	* gdb.ada/excep_handle.exp: Same.
	* gdb.ada/mi_string_access.exp: Same.
	* gdb.ada/mi_var_union.exp: Same.
	* gdb.arch/arc-analyze-prologue.exp: Same.
	* gdb.arch/arc-decode-insn.exp: Same.
	* gdb.base/readnever.exp: Same.
	* gdb.fortran/printing-types.exp: Same.
	* gdb.guile/scm-lazy-string.exp: Same.