Tests/Assembler: Drop -g when generating sample assembly source

Some compilers, such as Clang on OS X, do not want the -g flag for both
generating assembly code and assembling it.  Drop the -g flag from
generation of main.s in the Assembler test.
Merge topic 'test-Assembler-no-g' into next

f60797f Tests/Assembler: Drop -g when generating sample assembly source