Proposed new API call: testcase group {begin|end}

[Jacob Bachmeyer]

The new XML output will have a concept of test groups.  While the 
DejaGnu core can group tests by the scripts executed to run them, one 
test script can itself run multiple logically-distinct groups of tests.

This new API call will also introduce a new multiplex entrypoint 
"testcase" distinguished from the existing "testsuite" entrypoint by the 
extent of the data accessed.  The "testsuite" entrypoint is for querying 
data that does not change during a test run or for appending to internal 
data structures that are processed at some well-defined later time, 
while the new "testcase" entrypoint is for querying or modifying 
internal structures that track state that can vary as a single test 
script is executed.

API call:  testcase group begin <name>
API call:  testcase group end <name>
Begin or end test group <name> where <name> is either a string that may 
contain multiple /-delimited parts or a Tcl list that will be joined 
into such a string.  Each call to "testcase group begin" must have a 
matching call to "testcase group end" with exactly the same name in both 
calls and both calls must be in the same file.  Groups may nest to any 
depth, but must nest exactly; groups are internally tracked on a stack, 
onto which "begin" pushes an item and from which "end" pops the 
top-of-stack, which must match the provided name.

Initially, this API call will produce only a log message and verbose 
output, but will be tracked internally to validate its usage.  When the 
new XML output format is merged, groups will appear in the XML output.  
The current goal is to merge the new XML output for 1.7.

-- Jacob