Fix tags on broken SMT backend test

These various tests are either broken with error or timeout on
SMT backends, in particular cprover-smt or z3.

	# Please enter the commit message for your changes. Lines starting

Author: TGWDB

regression/cbmc/Float-div3/test.desc

@@ -1,4 +1,4 @@
-CORE
+CORE broken-z3-smt-backend
 main.c
 --floatbv
 ^EXIT=0$

regression/cbmc/Quantifiers-assertion/test.desc

@@ -1,4 +1,4 @@
-CORE
+CORE broken-z3-smt-backend
 main.c
 
 ^\*\* Results:$

regression/cbmc/Quantifiers-assignment/test.desc

@@ -1,4 +1,4 @@
-CORE
+CORE broken-z3-smt-backend
 main.c
 
 ^\*\* Results:$

regression/cbmc/Quantifiers-if/test.desc

@@ -1,4 +1,4 @@
-CORE
+CORE broken-z3-smt-backend
 main.c
 
 ^\*\* Results:$

regression/cbmc/Quantifiers-initialisation2/test.desc

@@ -1,4 +1,4 @@
-CORE
+CORE broken-z3-smt-backend
 main.c
 
 ^\*\* Results:$

regression/cbmc/Quantifiers-not-exists/fixed.desc

@@ -1,4 +1,4 @@
-CORE
+CORE broken-z3-smt-backend
 fixed.c
 
 ^\*\* Results:$

regression/cbmc/Quantifiers-not/test.desc

@@ -1,4 +1,4 @@
-CORE
+CORE broken-z3-smt-backend
 main.c
 
 ^\*\* Results:$

regression/cbmc/Quantifiers-two-dimension-array/test.desc

@@ -1,4 +1,4 @@
-CORE
+CORE broken-z3-smt-backend
 main.c
 
 ^\*\* Results:$

regression/cbmc/union10/union_list2.desc

@@ -1,4 +1,4 @@
-CORE
+CORE broken-z3-smt-backend
 union_list2.c
 
 ^EXIT=0$

regression/cbmc/union11/union_list.desc

@@ -1,4 +1,4 @@
-CORE
+CORE broken-z3-smt-backend
 union_list.c
 
 ^EXIT=0$