When gcc-dg-runtest is used to run a test the test is run several times
with different options. For clarity of the log, the test infrastructure
then append the options to the testname. This means that all the code
that must deal with the testcase itself (eg. removing the output files
after the test has run) needs to remove the option name.

There is already a pattern (see below) for this in several place of the
testsuite framework but it is also missing in many places. This patch
fixes all of these places. The pattern is as follows:

set testcase [testname-for-summary]
; The name might include a list of options; extract the file name.
set testcase [lindex $testcase 0]

2017-11-10  Thomas Preud'homme  <thomas.preudhomme@arm.com>

    gcc/testsuite/
    * lib/scanasm.exp (scan-assembler): Extract filename from testname used
    in summary.
    (scan-assembler-not): Likewise.
    (scan-hidden): Likewise.
    (scan-not-hidden): Likewise.
    (scan-stack-usage): Likewise.
    (scan-stack-usage-not): Likewise.
    (scan-assembler-times): Likewise.
    (scan-assembler-dem): Likewise.
    (scan-assembler-dem-not): Likewise.
    (object-size): Likewise.
    (scan-lto-assembler): Likewise.
    * lib/scandump.exp (scan-dump): Likewise.
    (scan-dump-times): Likewise.
    (scan-dump-not): Likewise.
    (scan-dump-dem): Likewise.
    (scan-dump-dem-not): Likewise

From-SVN: r254622