.travis.yml: fold --disable-tcg into alternate coroutine builds

The alternate coroutine builds are really only of interest to people
running KVM (although I think you could use them for TCG if you really
tried). As they tend to run long lets kill two birds with one stone
and fold the --disable-tcg build into them.
Signed-off-by: NAlex Bennée <alex.bennee@linaro.org>

.travis.yml

@@ -97,12 +97,16 @@ matrix:
         - CONFIG="--enable-modules --disable-linux-user"
 
 
+    # Alternate coroutines implementations are only really of interest to KVM users
+    # However we can't test against KVM on Travis so we can only run unit tests
     - env:
-        - CONFIG="--with-coroutine=ucontext --disable-linux-user"
+        - CONFIG="--with-coroutine=ucontext --disable-tcg"
+        - TEST_CMD="make check-unit -j3 V=1"
 
 
     - env:
-        - CONFIG="--with-coroutine=sigaltstack --disable-linux-user"
+        - CONFIG="--with-coroutine=sigaltstack --disable-tcg"
+        - TEST_CMD="make check-unit -j3 V=1"
 
 
     # Check we can build docs and tools
@@ -162,11 +166,6 @@ matrix:
         - TEST_CMD=""
 
 
-    - env:
-        - CONFIG="--disable-tcg"
-        - TEST_CMD=""
-
-
     # MacOSX builds
     - env:
         - CONFIG="--target-list=aarch64-softmmu,arm-softmmu,i386-softmmu,mips-softmmu,mips64-softmmu,ppc64-softmmu,riscv64-softmmu,s390x-softmmu,x86_64-softmmu"