Merge if and else tests to a single project.

test cases/common/15 if/meson.build

diff --git a/test cases/common/15 if/meson.build b/test cases/common/15 if/meson.build
index b0288db..f8d8295 100644
--- a/test cases/common/15 if/meson.build
+++ b/test cases/common/15 if/meson.build
@@ -58,3 +58,15 @@
 else
   message('Ok')
 endif
+
+# Test plain else
+
+var = false
+
+if var
+  exe = executable('break', 'break.c')
+else
+  exe = executable('eprog', 'prog.c')
+endif
+
+test('elsetest', exe)

test cases/common/16 else/meson.build

diff --git a/test cases/common/16 else/meson.build b/test cases/common/16 else/meson.build
deleted file mode 100644
index 99cb927..0000000
--- a/test cases/common/16 else/meson.build
+++ /dev/null
@@ -1,11 +0,0 @@
-project('else test', 'c')
-
-var = false
-
-if var
-  exe = executable('break', 'break.c')
-else
-  exe = executable('prog', 'prog.c')
-endif
-
-test('elsetest', exe)

test cases/common/16 else/prog.c

diff --git a/test cases/common/16 else/prog.c b/test cases/common/16 else/prog.c
deleted file mode 100644
index 78f2de1..0000000
--- a/test cases/common/16 else/prog.c
+++ /dev/null
@@ -1 +0,0 @@
-int main(void) { return 0; }